There is a red double-decker London night-bus called the Wandering Jewess. Tickets are free but you're only allowed on board if you have Jewish ancestry. I get on. It goes out into the countryside, among big arable fields. It makes brief regular stops, but no one gets on or off. At one stop my travelling companion and I get off to inspect the wildflowers by the side of the road, along the edge of a huge flat field. The bus starts to move off and we have to jump back on quickly before it pulls away.